What is Magun:

Magun, or thunderbolt, is a popular charm among the Yoruba people, commonly done to curb promiscuity. However, Some beliefs and traditions in Yoruba land have always been feared and revered, the Magun is one of those charms. In Yoruba land, any form of adultery is seen as a taboo and some are fond of taking precautions to curb promiscuity. 

In the Yoruba culture of the Western region of Nigeria, the strange tradition of Magun means “do not climb”. It is done to restrict either man or woman from sexual promiscuity. Parents can place magun on their daughters to keep them from being promiscuous and punish anyone who rapes them, or in-laws, lovers, and spouses could do it to keep husbands or wives from being unfaithful.
The magun is usually laid without consent or trickily. A broomstick or thread can be placed on a doorstep or walkway for the woman to cross over it. Nevertheless, the result can be very deadly. A woman with this unfaithful spell can get ridden with strange illnesses, boils, smallpox, or increased sweating, and could eventually die. A man with the spell who cheats could end up crowing like a rooster, enlargement of the private part, headaches, convulsions, or somersaulting.
However, the most common manifestation of this charm happens when a woman laid with the spell commits adultery, the penis of the lover becomes stuck in the vagina with severe pains until the husband comes to cancel the attack.

As it may be, Yoruba culture is not the only tribe with such a spell, especially on married women. Some Tribes have a normal culture whereby once a married woman sleeps with another man, her husband instantly falls sick and possibly dies from the illness if a prompt rescue by doing some certain cleansing and rituals is not done on time.

Whether you believe is friction, science, or real many known consequences have been recorded in history.